Control for pressing machines



March 30,-, 1937. J. M. DEWEY CONTROL FOR PRESSING ,MACHINES 2Sheets-Sheet 1 A 2% Ri 4 vmw Filed Oct. 23, l935 INVENTOR JAMES M. DEWEYATTORNEYS March 30, 1937.

J. M. DEWEY CONTROL FOR PRESSING MACHINES Filed Oct. 23, 1935 2SheetsSheet 2 INVENTOR JAMES M. DEWEY TTO EYJ Patented Mar. 30, 1937UNITED STATES PATENT OFFICE CONTROL FOR PRESSING MACHINES ApplicationOctober 23, 1935, Serial No. 46,244

12 Claims.

This invention relates to a pressing machine and more particularly toimprovements in operating and control mechanism therefor.

My improved control mechanism is applied 5 to a pressing machine inwhich two coacting pressing members are relatively moved toward eachother in two steps, a first step into preliminary or safe closedposition and a second step into final closed position. In such a press-10 ing machine I provide power means for causing the relative approachmovement between the pressing members with a control member for eachstep of the operation and improved mechanism for causing the operationof the second 15 step control member to follow automatically theoperation of the first step control member.

Another feature of my invention is the provision in a press of the typeabove described of a power device for actuating the second step controlmember together with means for actuating that power devicesimultaneously with the production of the first step of the closingoperation. My invention also provides a time delay period between theactuation of a first step control 25 member and the operation of thepower device for causing second step operation of the press closingmechanism.

Other features of my invention include the novel arrangement of certainportions of the control mechanism to carry out the above describedfunctions and the advantages of these various constructions will bepointed out as the description proceeds.

In the drawings, Fig. l is an end elevation 35 partly in section of apressing machine embodying my invention with the press parts in openposition and with the control mechanism shown diagrammatically; Fig. 2is a view similar to Fig. 1 showing the press parts in closed position.

While my invention may be applied to a pressing machine in which one ofa pair of coacting pressing members is held stationary while the othermember is moved by two step operation into engagement therewith, I havechosen to illus- 5 trate my invention as applied to a pressing machinein which each of the coacting pressing members is movable toward theother. The embodiment shown comprises a frame l supporting on a suitablebracket a pressing bed I l mov- 50 able vertically relative to the frameand guided during such movement by one or more suitable pins Ila whichslidingly engage a portion of the frame. On a bracket of the frame ispivotally mounted a head lever I2 at the forward end 55 of which iscarried a pressing head [3 for move-- ment into and out of coactingposition with the bed H. The head may be suitably heatedif desired. Thepressing head is moved to position adjacent the bed by a pair of togglelinks Hi and I5 connected between the rear end of the head lever and thelower rear portion of the frame. The toggles are biased toward brokenposition by a spring l6 and are moved into and beyond straightenedposition by a cylinder and piston motor ll. This motor comprises a cyl-10 inder Ila housing a piston llb whose rod H0 is connected with thetoggle links. The links are limited in their movement rearwardly bymutually engaging abutments Him and l5a. A combined snubber and togglekicking device 3 is supported on a suitable bracket and includes aplunger l 8w spring pressed outwardly.

The means for raising the pressing bed into final engagement with thehead after the latter has been placed in position adjacent it com prisesa cylinder and piston motor l9 mounted on the frame. This motorcomprises a cylinder Illa housing a piston I91) whose rod l9coperatively engages the bed.

Motive fluid is supplied to motor I! from a source of pressure fluid,such as conduit 20, and thence by way of valve casing 2|, conduit 22,valve casing 23 and conduit 24 to cylinder I 10.. Valve casing 2| housesa normally closed inlet valve 2Ia. having a stem 2 lb by which it may beactuated. Valve casing, 23 houses a valve disk 23a which in its normalposition as shown in Fig. 1 normally opens an outlet port 231) whileclosing an inlet port 230 but when actuated the valve disk closes theoutlet port and opens the inlet port. The valve disk is actuated by astem 23d and a manual 23e.

Motive fiuid is supplied to motor l9 by way of conduit 25, valve casing26 and conduit 21. Casing 26 houses a normally open outlet valve 260.and a normally closed inlet valve 26b mounted on a common stem 260 bywhich the valves may be actuated.

A power device indicated generally at 28 is provided for actuating thecontrol valves in casing 26. This power device provides a difierentialpiston construction including a piston 28a of greater diameter and apiston 28b of lesser diameter rigidly connected by a rod 280. This rodcarries a pin 28d which engages bellcrank 29 and more particularly thepin enters an elongated slot 29a in the bellcrank. The device 28 hassuitable cylinder portions 28c housing piston 28a and- 28f housingpiston 28b which are rigidly connected together by an intermediatehousing ing 34 and conduit 35. In conduit is located an adjustablerestricted orifice 36 which may be in the form of an adjustable needlevalve as shown. Valve casing 32 houses a valve 32a which is adapted toopen and close a port 321) in communication with cylinder 28 This valveis'biased in port closing direction by a spring- 32c and the valve isguided and actuated by a stem 32d which has a sliding fit with asuitable bore in piston 28?). The spring 320 is strong enough topreponderate over supply pressure entering through conduit 3! andexerted against the inner face of the disk 32a. Valve casing 34 houses avalve disk 34a which normally closes an outlet port 341) as shown in Figl but when actuated opens this outlet port and closes the normally openinlet port 340. The valve disk 34a is actuated by a stem 34d which isrigidly connected by a bracket 31 with the valve stem 2lb. Both of thesevalve stems may be actuated simultaneously therefore by movement ofmanual 38.

A press opening supply of fluid for the'power device 28 is suppliedthrough conduit 39, valve casing andconduitM. Casing 40 houses anormally closed inlet valve 40a mounted on a stem 40b and actuated by amanual 406. I

With the parts in the position-of Fig. 1, the operator arranges the layof the work upon the bed II and actuates manuals 23c and 38 to theposition shown in Fig. 2 This supplies motive fluid to motor I! throughconduit 20, valve 2| a,

conduit 22, valve 23a and conduit 24. Piston llbmakes a strokerearwardly or to the left as viewed in the drawings; which moves thetoggle links M and I5 to beyond straightened position thus placing thepressing head I3 in the position shown in 'Fig. 2, although it will beunderstood that as the pressing head reaches this position the bed isstill in the position of Fig. 1.

Normally the power device 28 is in the position shown in Fig. 1 becausemotive fluid under equal pressure is applied against the faces ofpistons 28b and 23a and the piston 28a, being of greater area thecombined piston device and rod 280 moves to the right and remains in theposition of Fig. 1 as the force exerted on piston 28a is greater thanthe force exerted by spring 320. Upon actuation of manual 38 as abovedescribed, the inlet port 340 is closed, thus cutting off the fluidsupply for cylinder 286. At the same time outlet port 34b is opened sothat evacuation of cylinder 280 is initiated. This evacuation takesplace at a restricted rate because of the needle valve 36 and it willrbeunderstood that'thisrate can be controlled by the adjustment of theneedle valve. It follows therefore that after a suitable timed delay thepressure against piston 28bpreponderates overthe pressure exertedagainst piston 28a'and the two pistons'an'd their connecting rod 280move toward the left into the position of Fig. 2. As the parts moveover, spring'32c closes valve 32a and when the pistons reach theposition of Fig. 2 bell crank 29 is moved clockwise sufficiently toactuate the valves in casing l6'thus because the upward pressure ofthe'pressing bed holds the toggle links in their beyond straight:

ened position.

.To open the press manual 400 is actuated thus supplying fluid throughconduit 39, valve 40a and conduits 4i and 35 to cylinder 28a. Thepressure againstpiston 28a then preponderates over the force exerted onpiston 28b and returns the parts of the power device 28 to the positionshown in Fig. l whereupon the valves in casing 26 are returned to theirnormal position as shown in Fig. 1 by the actuating spring and cylinderI90, is evacuated. Bed I I then moves down due to the action of gravityand the toggle links are moved toward their broken position by thecombined action of the kick device l8 and spring l6.

It will be understood that in actual construction the manuals 23c and 36are placed at the front of the press in position before the operator andso spaced apart that they require a hand of the operator on each of themfor their actuation. I thus provide a safe control mechanism for apressing machine of this type which prevents injury to an operator'shands becauseboth manuals 23e and 38 must be actuated to supply power tothe head moving motor l1 and one of these safety control membersinitiates the raising of the bed which finally closes the press.

What I claim is:

1. In a pressing machine, a pair of coacting relatively movable pressingmembers, 7 power means for causing relative approach movement betweensaid membersin two steps, a first step into preliminary closed positionand a second step into final closed position control members for saidpower means, one control member for causing each step of the operationthereof, a power device for actuating and holding actuated said secondstep control member, and means for actuating said power device byoperation of said first step control member, said last named meansincluding an arrangement for delaying operation of said device for aninterval after operation of means for moving. said other member intoengagement with said one member, a control member forsaid last namedpower means, a power device for operating said last named control mem-'ber, and'means for actuating said power device by movement of said firstnamed control memberf into power supply position. 7 3. In a'pressingmachine, a pair of coacting relativelyamovable pressing members, powermeans for causing relative, approach movement between said membersin twosteps, a first step into preliminary closed position anda second step 5into final closed position, control members for said power means, onecontrol member for causing each step of the operation thereof, a powerdevice for actuating and holding actuated said second step controlmember, said device being biased in control member actuating direction,fiuid means normally holding said device against the force of itsbiasing means, and means for exhausting fluid from said fluid means byactuation of said first step control member.

4. The combination of claim 3, and in which said exhausting meansincludes a restricted orifice for delaying exhaust from said fluidmeans.

5. The combination of claim 3, and in which said fluid means includes asupply conduit, a normally open valve therein, and means for closingsaid valve upon movement of said device insecond-step-control-member-actuating direction.

6. In a pressing machine, a pair of coacting relatively movable pressingmembers, power means for causing relative approach movement between saidmembers in two steps, a first step into preliminary closed position anda second step into final closed position, control means for said powermeans including two spaced safety control members for controlling firststep operation of said power means, a second step control member forsaid power means, a power device for actuating said second step controlmember, means biasing said device in control member actuating direction,fiuid means normally holding said device against the force of itsbiasing means, a normally closed outlet valve for exhausting saidfiuidmeans, and an operative connection between said valve andone ofsaid safety control members for opening said valve by actuation of thesaid safety control member.

7. In a pressing machine, coacting head and bed pressing members, eachmovable toward the other, a first motor and mechanism associatedtherewith for moving said head into position adjacent said bed, saidmechanism being arranged to hold said head in said position inresistance to pressure from said bed, a second motor for moving said bedinto engagement with said head I when the latter is in said adjacentposition, a

control member for said first motor, and means independent of said firstmotor for actuating said second motor in press-closing direction bymovement of said control member in press-closingproducing direction.

8. A pressing machine as in claim 7, and in which said last named meansincludes means for delaying actuation of said second motor followingmovement of said control member.

9. In a pressing machine, coacting head and bed pressing members, eachmovable toward the other, a first motor and mechanism associatedtherewith for moving said head into position adjacent said bed, saidmechanism being arranged to hold said head in said position inresistance to pressure from said bed, a second motor for moving said bedinto engagement with said head when the latter is in said adjacentposition, a control member for each motor, a device for actuating saidsecond motor control member, said device including mutually opposedmovable abutments of greater and lesser areas adapted as onepreponderates over the other to move said de- 7 vice into positionscorresponding to off and on positions respectively of said controlmember, fiuid supply lines for conducting pressure fluid against each ofsaid abutments, said supply line for said abutment of greater areaincluding a normally closed outlet valve, and means for opening saidoutlet valve coincidently with movement of said first motor controlmember in motor energizing direction.

10. In a pressing machine, coacting head and bed pressing members, eachmovable toward the other, a first motor and mechanism associatedtherewith for moving said head into position adjacent said bed, saidmechanism being arranged to hold said head in said position inresistance to pressure from said bed, a second motor for moving said bedinto engagement with said head when the latter is in. said adjacentposition, a pair of spaced safety control members adapted uponsimultaneous actuation to energize said first motor, a second motorcontrol member, a device for actuating said second motor control member,said device including mutually opposed movable abutments of greater andlesser areas adaptedas one preponderates over the other to move saiddevice into positions corresponding to off and on positions respectivelyof said control member, fluid supply lines for conducting pressure fiuidagainst each of said abutments, said supply line for said abutment ofgreater area including two valves in series, one valve movable intofluidsupply and fiuid-cut-off positions by said device uponpreponderation of said greater and lesser abutments respectively overthe other, the other valve being a normally closed outlet valve, andmeans for opening said outlet valve coincidently with movement of one ofsaid safety control members in motor energizing direction.

11. A pressing machine and control mechanism as in claim 10, includingmeans for adjustably restricting the flow through said normally closedoutlet valve.

12. In a pressing machine, a pair of coacting relatively movablepressing members, power means for causing relative approach and pressingaction between said members in two phases, a first phase to causepreliminary movement into a preliminary closed position and a secondphase into final closed position, two spaced safety con-' trol membersfor said power means adapted upon

